Session 7

Question 1

Patch dynamics

Answer 1

Incursion and melding of patches over time as a function of disturbance events and successional growth of vegetation

Question 2

Patch connectivity

Answer 2

Degree of adjacency of patches with similar conditions in a landscape

Question 3

Patch isolation

Answer 3

Distance from one patch type to the next (or nth) nearest patch of the same

Question 4

Fragmentation

Answer 4

Breaking up of contiguous environmental or habitat patches into smaller, more disjunct, or isolated patches of different types

Question 5

Connectivity

Answer 5

Degree of adjacency of patches of similar conditions within a landscape

Question 6

Permeability

Answer 6

Degree to which an organism can move among patches within a landscape

Question 7

Faunal relaxation

Answer 7

When wildlife species are lost from an isolated environment

Question 8

Edge effect

Answer 8

Incursion of microclimate and vegetation into a patch, typically forested from a disturbed edge or opening

Question 9

Edge contrast

Answer 9

Degree of difference in vegetation structure b/w two adjacent patches

Question 10

Habitat heterogeneity

Answer 10

The degree of discontinuity in environmental conditions across a landscape for a particular species

Question 11

Ecotones

Answer 11

discontinuities in environmental conditions – it refers to the new area (transition area) made by merging the two separate zones together.

Question 12

Ecolines

Answer 12

broader gradations in conditions over areas of greater geographic extent

Question 13

Corridors

Answer 13

Linear arrays in an environment to connect patches

Question 14

Describe the three degrees of species-specific habitat heterogeneity: extreme, partial, and temporal

Answer 14

extreme cases: resource or vegetation patches can be isolated into islands surrounded by vastly different and, for specific species, unsuitable conditions.

‘partial isolation’ : can affect population viability
- by incrementally lowering the numbers of animals per unit area of unsuitable and suitable environments,
- by lowering dispersal, and
- by lowering the effective size of the breeding populations,
- even though a substantial decline in overall abundance might not be evident

temporal fragmentation’: refers to the degree to which a particular environment (e.g., successional stage of a vegetation type) occupies a specific area through time

Question 15

What 5 factors must be considered when considering species-specific habitat fragmentation?

Answer 15

 absolute loss of habitat area (less patch interior),
 increased edge,
 increased distances for movement of animals between patches,
 increased penetration of predators, competitors, and nest parasites,
 changes in microclimate with changes in patch area and edge.

Question 16

Given the discussion on habitat fragmentation, what is a common and very important point to be aware of?

Answer 16

• no general statements can be made concerning how environmental conditions will influence populations of predators that negatively impact target species for restoration.

Question 17

What four concepts should be considered for incorporating fragmentation issues into research and planning?

Answer 17

choice of spatial scale dramatically affects the development of restoration plans.

Patch types and definitionsaffect analyses;

perimeter : area ratios should not be used as measures of fragmentation.

Measure different aspects of fragmentation separately

Question 18

Describe the four disturbance categories and include examples. How can these disturbances influence the abiotic and biotic environments?

Answer 18

Type 1
* Major environmental catastrophe (volcanoes, major fires, hurricanes)

Type 2
* Local environmental disturbance (Wind, ice storms, disease)

Type 3
* Chronic or systematic change over wide areas (predators, competition, forestry)

Type 4
* Minor environmental change (local fires, developments)

Question 19

What are some conclusions that can be made about disturbances and dynamics of resource patches?

Answer 19

• response to each type of disturbance is species-specific,
• Type I disturbances will, in general, have much more comprehensive and catastrophic impacts on species relative to Type IV disturbances
• closer disturbance mimics natural processes, and better-adapted species to accommodate changes
• thus, the further the human activities alter patch disturbance dynamics from natural processes, the greater the discontinuity occurs between the altered habitat and the species’ ability to use it (niche requirements).

Question 20

What are some of the limitations around using indicator or umbrella species and wildlife habitat models to direct management in fragmented landscapes?

Answer 20

• one taxon usually fails to predict the response of other groups to environmental change

Question 21

Describe the typical design of a reserve and corridor complex.

Answer 21

the corridor extending out of the central (“core”) part of the reserve,

design allows movement of animal species of all sizes:
 first, as a passage route for species that can live in the core (or patch)
- but who are too large to have the majority of their home range contained within the more narrow corridor, such as medium and large mammals;
 second, as an extension of the core that allows some degree of residency in the corridor, if not breeding opportunities, such as small mammals and small to medium birds.

Question 22

What controversial points should be noted about corridors in wildlife restoration? (4 points)

Answer 22

• corridors can enhance the spread of fires, and can increase exposure of individuals to predation, domestic animals, and poachers
• corridors can increase the transmission of disease, increasing metapopulation extinction risk
• Not enough info for wholesale adoption of corridors, we must carefully evaluate them plan on a species-specific basis

Question 23

Describe the 4 corridor designs and their features

Answer 23

• classic depiction of a corridor (Figure 7.3A) is a continuous passageway of some width that links two or more core habitat areas.
• Because a continuous linkage might not be possible or even required the stepping-stone concept of corridors (B) has been proposed
• The stepping-stone concept can also be expanded to include actual linkages between the steps (C)
• Finally (D), the corridor is a lower-quality area relative to the core habitat

Question 24

What is the best corridor design; explain your answer.

Answer 24

no best corridor configuration.
species-specific concept.

Question 25

There are numerous factors that must be considered when determining if corridors are a viable option within a restoration project – please state as many as possible (9).

Answer 25

• corridors will usually promote the movement of some individuals of certain species,
• poorly designed corridors will act as filters that tend to allow passage of generalist species, such as those that use multiple habitat types,
• specialist species are unlikely to use poorly designed corridors,
• intraspecific and interspecific interactions are important factors to consider in connectivity planning, and social species might not use corridors unless they can move in groups.
• species with physical limitations will need special approaches to corridor design,
• all possible barriers should be identified in the planning process,
   must avoid corridors that look good on paper, but
   do not adequately serve species of interest.
   it may be necessary to replace human-created barriers, such:
• e.g., fences or poorly designed culverts.
• continuous corridors are preferred to those bisected by roads or other barriers,
   if the habitat within a corridor is too fragmented, passage of species through the corridor may effectively be stopped.
   gaps and barriers, such as roads, should be avoided where possible.
• length and width of corridors naturally are central to the ultimate utility of a corridor.

Question 26

Explain the concepts (purpose, the reason for use, when they should be used, etc.) of ‘buffers.’

Answer 26

Potentially, land-use zoning can influence activities surrounding the reserve and make them more compatible with project goals.

Activities within the buffer zone would be designed to minimize impacts on the core area (Figure 7.4).
* e.g., if logging was allowed in the transition zone, then perhaps only camping would be permitted in the buffer,
* or, hunting might be allowed in the transition zone but not in the buffer & core.

However, why not extend the core area to the edge of the transition zone,
* thus providing at least the opportunity for a greater extent of the core,
* this is often difficult to implement because of political considerations.

The buffer can, in essence, become the corridor connecting core areas, if conditions are appropriate for species of interest.

Question 27

What are some of the adverse genetic effects associated with isolation (5)?

Answer 27

• fixation of deleterious alleles,
• increasing homozygosity, and
• overall decline in allelic diversity of the gene pool, as caused by genetic drift.

Inbreeding depression, which includes:
* depressed fertility and fecundity,
* increased natal mortality, and
* decreasing the age of reproductive senescence,

Founder effects resulting from small initial populations,
* this sets the stage for loss of genetic and phenotypic diversity with subsequent isolation from outbreeding

At the assemblage (community) level:
* recent isolation can result in a decline in species richness over time.

Question 28

How does isolation influence extinction and colonization rates (make reference to native and non- native species (4).

Answer 28

Isolation, combined with a small patch size can result in:
* Extinction (extirpation) rates exceeding colonization rate of native species, and
* colonization rates exceed extinction (extirpation) rates for exotic species.
* smaller and more isolated the reserves are, the greater both processes occur,
* if islands (reserves) are sink habitat for native species – the faster this imbalance occurs.

Question 29

When would isolation be a benefit to a population?

Answer 29

• avoiding spread of disease, parasites, and pathogens,
• establishing of several founder populations in sites with different disturbance dynamics and thus different likelihoods of success
• maintaining relictual faunas naturally isolated by changes in climate, vegetation, or landform

Question 30

What are the 7 major principles of reserve design?

Answer 30

• larger blocks containing larger populations are better than small blocks,
• blocks of habitat close together are better than blocks far apart,
• habitat in continuous blocks is better than fragmented habitat,
• interconnected blocks of habitat are better than isolated blocks,
• species well distributed are less susceptible to extinction than are species confined to small locations,
• populations that fluctuate are more vulnerable than stable populations,
• disjunct or peripheral populations are likely to be more genetically impoverished and vulnerable to extinction,
   but are also more genetically distinct than central (core) populations.

Question 31

What 4 points should be considered when maintaining within patch conditions?

Answer 31

• topographic location,
• adjacency of other patches (metapopulation structure), and
• susceptibility to disturbances such as floods or fires,
• the species-specific requirements.

Question 32

What may influence patch occupancy by a species over time (3)?

Answer 32

• the size and quality of the patches,
• the spatial juxtaposition of the patches.
• the type and quality of the intervening matrix environment

Question 33

There are 4 guidelines for habitat configuration, what are these guidelines?

Answer 33

• Habitat patches should remain reachable by dispersing and migrating individuals, and organisms moving within their home ranges.
• Feeding and resting habitats can be provided within daily dispersal distances or home range areas.
• Secondary or marginal habitats can be provided as peripheral habitats to help serve as sinks for surplus or floater individuals in good reproductive years
• Expanding the area of habitat allows the number of individuals of a species to increase

Question 34

Detail the 5 factors that potentially limit the occurrence of species in a proposed restoration area.

Answer 34

Biotic factors, including predation and competition

Disturbance caused by human activities

Disease

Size of area

Seasonality